Improvement in reusing alkaline solutions from treating straw



.I. H. DUGAN.

Rousing Alkaline Solutions from Treat i'ng ,Straw.

Patented Deb. 9,1873. i

WITNESSES.

UNITED STATES PATENT QFFICE.

JAMES II. DUGAN, OF BLOOMFIELD, NEIV JERSEY.

IMPROVEMENT IN REUSING ALKALINE SOLUTIONS FROM TREATING STRAW.

Specification forming part of Letters Patent No. 145,409, dated Decrmber 9,1873; application filed October 26, 1872.

To all whom it may concern Be it known that I, JAMES H. DUGAN, of Bloomfield, Essex county, New Jersey, have invented an Improvement in the Reuse of Alkaline Solutions, of which the following is,

treatment of another batch of fibrous material.

In carrying my invention into efi'ect, I employ apparatus, substantially as illustrated in the accompanying drawing, in which A represents a cylindrical tank, having trunnions a (1 adapted to hearings on a suitable frame. Into this tank I place the vegetable fibrous material to be treated, together with a suitable quantity of a solution of caustic alkali. While the tank revolves a jet of steam from a pipe, I), is introduced to it through one of the trunnions a. After the material has been't-reated for a suitable length of time, the cover d of a man-hole in the tank is removed, and the contents are permitted to fall onto a slotted 9r perforated platform in a tank, B, the fluid contents flowing through the platform into the tank, while the stock remains on the platform, where it is thoroughly washed preparatory to its removal, the water with which the material is washed taking up the alkali which remains in the fibers, and falling into the tank below. From the tank B the alkaline solution is forced through a pipe, f, into a reservoir, D, having a perforated diaphragm, h, supporting suitable filtering material 1', through which the fluid percolates, leaving behind all particles of iibrous material and other foreign matter which it had held in suspension. The filteredliquid is, consequently, in the requisite pure condition to be restored to and reused in the revolving digesting-tank. It is, however, first pumped into the reservoir E during the time the digesting-tank is in operation, so that when this tank is emptied there will be a supply from which'it can be at once replenished. The alkaline solution necessarily loses much of its strength from the time it leaves the digestingtank until it reaches the reservoir E; hence, it becomes necessary to re-enforce it with a proper quantity of fresh caustic alkali before it is returned to the digesting-tank.

I do not claim, broadly, the re-enforeing of alkaline solutions in the manufacture of paperpulp; but

I claim The combination, with a tank, A, of a draining-tank, B, and filtering-reservoir D, operating together, as and for the purpose specified.

In testimony whereof I have signed my ,name to this specification in the presence of two subscribing witnesses.

4 JAMES H. DUGAN.

Vitnesses ABRAHAM ll/IANNERS, DANIEL E. DUGAN. 

